Controlling odor in photopolymerization

ABSTRACT

The use of certain organic materials having non-aromatic carbon-carbon unsaturation is described in connection with photopolymerizable compositions containing aromatic sulfonium complex salt photoinitiators in order to minimize or eliminate the odor of organosulfur reaction by-products.

This is a division of application Ser. No. 876,113, filed Feb. 8, 1978now U.S. Pat. No. 4,218,531.

BACKGROUND OF THE INVENTION

This invention relates to photopolymerizable compositions.

The use of aromatic sulfonium complex salts as photoinitiators for thepolymerization of epoxides and other cationically polymerizablematerials has been described, for example, in U.S. Pat. Nos. 4,058,400and 4,058,401. Although for many applications such photopolymerizablecompositions produce very satisfactory products, under certainconditions such compositions may emit an offensive odor which ischaracteristic of certain organosulfur compounds. Accordingly, thepresence of such an odor effectively inhibits the use of coatedsubstrates in areas such as food applications.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided aphotopolymerizable composition comprising:

(a) a first organic material containing epoxide functionality and beingpolymerizable to higher molecular weight;

(b) aromatic sulfonium complex salt, said salt being photodecomposableand being capable of initiating polymerization of said organic materialupon exposure to actinic radiation; and

(c) a second organic material containing at least one site ofnon-aromatic carbon-carbon unsaturation.

DETAILED DESCRIPTION OF THE INVENTION

The epoxides which are useful in the present invention are any organiccompounds having an oxirane ring (i.e. ##STR1## polymerizable by ringopening. Such materials, broadly called epoxides, include monomericepoxy compounds and epoxides of the polymeric type and can be aliphatic,cycloaliphatic, aromatic or heterocyclic. These materials generallyhave, on the average, at least 1.5 polymerizable epoxy groups permolecule (preferably two or more epoxy groups per molecule). Thepolymeric epoxides include linear polymers having terminal epoxy groups(e.g. a diglycidyl ether of a polyoxyalkylene glycol), polymers havingskeletal oxirane units (e.g. polybutadiene polyepoxide), and polymershaving pendant epoxy groups (e.g. a glycidyl methacrylate polymer orcopolymer). The epoxides may be pure compounds but are generallymixtures containing one, two, or more epoxy groups per molecule. The"average" number of epoxy groups per molecule is determined by dividingthe total number of epoxy groups in the epoxy-containing material by thetotal number of epoxy molecules present.

These epoxy-containing materials may vary from low molecular weightmonomeric materials to high molecular weight polymers and may varygreatly in the nature of their backbone and substituent groups. Forexample, the backbone may be of any type and substituent groups thereoncan be any group free of an active hydrogen atom which is reactive withan oxirane ring at room temperature. Illustrative of permissiblesubstituent groups are halogens, ester groups, ethers, sulfonate groups,siloxane groups, nitro groups, phosphate groups, etc. The molecularweight of the epoxy-containing materials may vary from 58 to about100,000 or more. Mixtures of various epoxy-containing materials can alsobe used in the compositions of this invention.

Useful epoxy-containing materials include those which containcyclohexene oxide groups such as the epoxycyclohexanecarboxylates,typified by 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate,3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexanecarboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate. For amore detailed list of useful epoxides of this nature, reference is madeto the U.S. Pat. No. 3,117,099, incorporated herein by reference.

Further epoxy-containing materials which are particularly useful in thepractice of this invention include glycidyl ether monomers of theformula ##STR2## where R' is alkyl or aryl and n is an integer of 1 to6. Examples are the glycidyl ethers of polyhydric phenols obtained byreacting a polyhydric phenol with an excess of chlorohydrin such asepichlorohydrin (e.g. the diglycidyl ether of2,2-bis-(2,3-epoxypropoxyphenol)propane). Further examples of epoxidesof this type which can be used in the practice of this invention aredescribed in U.S. Pat. No. 3,018,262, incorporated herein by reference,and in "Handbook of Epoxy Resins" by Lee and Neville, NcGraw-Hill BookCo., New York (1967).

There is a host of commercially available epoxy-containing materialswhich can be used in this invention. In particular, epoxides which arereadily available include octacecylene oxide, epichlorohydrin, styreneoxide, vinyl cyclohexene oxide, glycidol, glycidylmethacrylate,diglycidyl ether of Bisphenol A (e.g. those available under the tradedesignations "Epon 828", "Epon 1004" and "Epon 1010" from Shell ChemicalCo., "DER-331", "DER-332", and "DER-334", from Dow Chemical Co.),vinylcyclohexene dioxide (e.g. "ERL-4206" from Union Carbide Corp.),3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexene carboxylate (e.g."ERL-4221" from Union Carbide Corp.),3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexenecarboxylate (e.g. "ERL-4201" from Union Carbide Corp.),bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate (e.g. "ERL-4289" fromUnion Carbide Corp.), bis(2,3-epoxycyclopentyl) ether (e.g. "ERL-0400"from Union Carbide Corp.), aliphatic epoxy modified with polypropyleneglycol (e.g. "ERL-4050" and "ERL-4052" from Union Carbide Corp.),dipentene dioxide (e.g. "ERL-4269" from Union Carbide Corp.), epoxidizedpolybutadiene (e.g. "Oxiron 2001" from FMC Corp.), silicone resincontaining epoxy functionality, flame retardant epoxy resins (e.g."DER-580", a brominated bisphenol type epoxy resin available from DowChemical Co.), 1,4-butanediol diglycidyl ether of phenolformaldehydenovolak (e.g. "DEN-431" and "DEN-438" from Dow Chemical Co.), andresorcinol diglycidyl ether (e.g. "Kopoxite" from Koppers Company,Inc.).

Still other epoxy-containing materials are copolymers of acrylic acidesters of glyc dol such as glycidylacrylate and glycidylmethacrylatewith one or more copolymerizable vinyl compounds. Examples of suchcopolymers are 1:1 styreneglycidylmethacrylate, 1:1methylmethacrylate-glycidylacrylate and a 62.5:24:13.5methylmethacrylate-ethyl acrylate-glycidylmethyacrylate.

Other useful epoxy-containing materials are well known and include suchepoxides as epichlorohydrins, e.g. epichlorohydrin; alkylene oxides,e.g. propylene oxide, styrene oxide; alkenyl oxides, e.g. butadieneoxide; glycidyl esters.

The compositions of the invention may also contain hydroxyl-containingmaterial which is copolymerizable with the epoxy. Thehydroxyl-containing material which is useful may be any liquid or solidorganic material having hydroxyl functionality of at least 1, andpreferably at least 2. Also, the hydroxyl-containing organic material isfree of other oxirane-reactive "active hydrogens". The term "activehydrogen" is well known and commonly used in the art, and as used hereinit generally corresponds to active hydrogen as determined by the methoddescribed by Zerewitinoff in J. Am. Chem. Soc., Vol. 49, 3181 (1927),incorporated herein by reference. Of course, the hydroxyl-containingmaterial is also substantially free of groups which may be thermally orphotolytically unstable; that is, the material will not decompose orliberate volatile components at temperatures below about 100° C., or inthe presence of actinic radiation which may be encountered during thedesired curing conditions for the photocopolymerizable composition.

Preferably the organic material contains two or more primary orsecondary aliphatic hydroxyl groups (i.e. the hydroxyl group is bondeddirectly to a non-aromatic carbon atom). The hydroxyl groups may beterminally situated, or they may be pendent from a polymer or copolymer.The molecular weight (i.e. number average molecular weight) of thehydroxyl-containing organic material may vary from very low (e.g. 62) tovery high (e.g. one million or more). The equivalent weight (i.e. numberaverage equivalent weight) of the hydroxyl-containing material ispreferably in the range of about 31 to 5000. When materials of higherequivalent weight are used they tend to reduce the rate and extent ofcopolymerization.

Representative examples of suitable organic materials having a hydroxylfunctionality of 1 include alkanols, monoalkyl ethers ofpolyoxyalkyleneglycols, monoalkyl ethers of alkylene-glycols, and othersknown to the art.

Representative examples of useful monomeric polyhydroxy organicmaterials include alkylene glycols (e.g. 1,2-ethanediol,1,3-propanediol, 1,4-butanediol, 2-ethyl-1,6-hexanediol,bis(hydroxymethyl)cyclohexane, 1,18-dihydroxyoctadecane,3-chloro-1,2-propanediol), polyhydroalkanes (e.g. glycerine,trimethylolethane, pentaerythritol, sorbitol) and other polyhydroxycompounds such as N,N-bis(hydroxyethyl) benzamide, 2-butyne-1,4-diol,4,4'-bis(hydroxymethyl)diphenyl-sulfone, caster oil, etc.

Representative examples of useful polymeric hydroxy-containing materialsinclude polyoxyethylene and polyoxypropylene glycols and triols ofmolecular weights from about 200 to about 10,000, corresponding toequivalent weights of 100 to 5000 for the diols or 70 to 3300 fortriols; polytetramethylene glycols of varying molecular weight;copolymers of hydroxypropyl and hydroxyethyl acrylates and methacrylateswith other free radical-polymerizable monomers such as acrylate esters,vinyl halides, or styrene; copolymers containing pendent hydroxy groupsformed by hydrolysis or partial hydrolysis of vinyl acetate copolymers,polyvinylacetal resins containing pendent hydroxyl groups; modifiedcellulose polymers such as hydroxyethylated and hydroxypropylatedcellulose; hydroxy-terminated polyesters and hydroxy-terminatedpolylactones; and hydroxy-terminated polyalkadienes.

Useful commercially available hydroxyl-containing materials include the"Polymeg"]R series (available from Quaker Oats Company) ofpolytetramethylene ether glycols such as "Polymeg" 650, 1000 and 2000,"PeP" series (available from Wyandotte Chemicals Corporation) ofpolyoxyalkylene tetrols having secondary hydroxyl groups such as "PeP"450, 550, and 650; "Butvar" series (available from Monsanto ChemicalCompany) of polyvinylacetal resins such as "Butvar" B-72A, B-73, B-76,B-90 and B-98; and "Formvar" 7/70, 12/85, 7/95S, 7/95E, 15/95S and15/95E; "PCP" series available from Union Carbide) of polycaprolactonepolyols such as "PCP" 0200, 0210, 0230, 0240, 0300; "Paraplex U-148"(available from Rhom and Haas), an aliphatic polyester diol, "Multron" Rseries (available from Mobay Chemical Co.) of saturated polyesterspolyols such as "Multron" R-2, R-12A, R-16, R-18, R-38, R-68 and R-74;"Klucel E" (available from Hercules Inc.) a hydroxypropylated cellulosehaving an equivalent weight of approximately 100; and "Alcohol SolubleButyrate" (available from Eastman Kodak) a cellulose acetate butyrateester having a hydroxyl equivalent weight of approximately 400.

The amount of hydroxyl-containing organic material which may be used inthe compositions of the invention may vary over broad ranges, dependingupon factors such as the compatibility of the hydroxyl-containingmaterial with the epoxide, the equivalent weight and functionality ofthe hydroxyl-containing material, the physical properties desired in thefinal cured composition, the desired speed of photocure, etc.

Generally speaking, with increasing amounts of hydroxyl-containingmaterial in the composition the cured product exhibits improved impactresistance, adhesion to substrates, flexibility, and decreased shrinkageduring curing, and correspondingly there is a gradual decrease inhardness, tensile strength and solvent-resistance.

Although both mono-functional and poly-functional hydroxyl-containingmaterials provide desirable results in the compositions of theinvention, use of the poly-functional hydroxyl-containing materials ishighly preferred for a majority of applications, although themono-functional hydroxyl-containing materials are particularly effectivein providing low viscosity, solvent-free coating compositions. Whenusing hydroxyl-containing organic materials having a functionalitysignificantly less than 2 (e.g. 1 to 1.5), amounts greater than about0.2 equivalent of hydroxyl per equivalent of epoxy tend to provide curedcompositions which are generally low in internal strength and tensilestrength and are susceptible to solvent attack, and consequently may beunsuitable for many applications. This tendency becomes increasinglymore apparent with increasing equivalent weight of thehydroxyl-containing material. Accordingly, when using mono-functionalhydroxy materials it is preferred that the equivalent weight thereof beno greater than about 250.

When poly-functional hydroxyl-containing material is used it may be usedin any amount, depending upon the properties desired in the curedcomposition. For example, the ratio of equivalents ofhydroxyl-containing material to equivalents of epoxide may vary fromabout 0.001/1 to 10/1. For applications where one primarily desiresflexibilization of an epoxy resin (e.g. for protective coatings onmetal) ratios as low as 0.001/1 provide improved results. Forapplications where the epoxide is present primarily as an insolubilizingagent for a polyhydroxy-containing film-forming theremoplastic organicmaterial (e.g. coatings for printing plates), ratios of hydroxylequivalents to epoxide equivalents may be as high as 10/1. Generallyspeaking, the higher the hydroxyl equivalent weight the more effectivesuch material is in imparting a given degree of toughness andflexibility to the cured composition.

Mixtures of hydroxyl-containing materials may be used, when desired. Forexample, one may use mixtures of two or more poly-functionalhydroxy-materials, one or more mono-functional hydroxy materials withpoly-functional hydroxy materials, etc.

The complex salts which are useful in this invention can be preparedusing conventional techniques described in the literature. For example,the aromatic sulfonium complex salts can be made by the procedure shownin J. W. Knapczyk and W. E. McEwen, J. Am. Chem. Soc., 91, 145, (1969);A. L. Maycock and G. A. Berchtold, J. Org. Chem. 35, No. 8, 2532 (1970);H. M. Pitt, U.S. Pat. No. 2,807,648, E. Goethals and P. De Radzetzky,Bul. Soc. Chim. Bleg., 73 546 (1964); H. M. Leicester and F. W.Bergstrom, J. Am. Chem. Soc., 51 3587 (1929), etc.

The useful complex salts are those of the formula

    [(R).sub.a (R.sup.1).sub.b (R.sup.2).sub.c S].sub.d ⊕[MQ.sub.e ].sup.-(e-f)

where R is a monovalent aromatic organic radical, R¹ is a monovalentorganic aliphatic radical selected from alkyl, cycloalkyl andsubstituted alkyl, R² is a polyvalent organic radical forming aheterocyclic or fused ring structure selected from aliphatic radicalsand aromatic radicals, M is a metal or metalloid, Q is a halogenradical, a is a whole number equal to 0 to 3 inclusive, b is a wholenumber equal to 0 to 2 inclusive, c is a whole number equal to 0 or 1,where the sum of a+b+c is a value equal to 3, d+e-f, f=valence of M andis an integer equal to from 2 to 7 inclusive, e is greater than f and isan integer having a value up to 8.

Particularly preferred complex salts are those in which M is boron,phosphorus, arsenic, or antimony, and particularly those in which theanion is BF₄ ⁻, PF₆ ⁻, SbF₆ ⁻ or AsF₆ ⁻. Anions which are slightlyhydrolyzed, e.g. SbF₅ OH⁻, are considered to be the full equivalent ofthe unhydrolyzed form of the anion for the purposes of this invention.

The second organic material which is included in the compositions of theinvention is of the type which has at least one site of non-aromaticcarbon-carbon unsaturation. The material is soluble in the polymerizablecomposition and does not deleteriously affect the polymerization of suchcomposition. The preferred organic materials are of the type in whichthe unsaturation is a carbon-carbon double bond wherein at least one ofthe carbon atoms is bonded to a ##STR3## and in which neither of saidcarbon atoms is bonded to more than one hydrogen atom. The mostpreferred organic materials is that of the type wherein the carbon atomwhich is not bonded to the ##STR4## is bonded to an aromatic radical.

Representative useful organic materials include ##STR5## where Ar is anaromatic radical such as phenyl, chlorophenyl, naphthyl and the like, Ris hydrogen or lower alkyl, benzyl, chloroalkyl, etc.; ##STR6## and2-butene-1,4-diol.

The amount of such organic material present in the photopolymerizablecompositions is not critical, it generally being present in an amountranging from about 0.5 to 20% by weight of the polymerizablecomposition. Preferably such material is present in an amount of about 1to 10% by weight. Generally, the amount of such material present isabout 0.5 to 3 times as great as the amount of complex saltphotoinitiator present.

For convenience, it is possible to prepare a photoinitiator concentrateconsisting essentially of hydroxyl-containing material, complex saltphotoinitiator, and the second organic material, in such proportionsthat the composition may be simply diluted with epoxy resin to formphotopolymerizable coating compositions. For these purposes thepreferred class of hydroxyl-containing materials are normally liquidoxyethylene-containing materials of the formula:

    H(OC.sub.2 H.sub.4).sub.n (OC.sub.3 H.sub.6).sub.m OH      I

where n+m is in the range of 2 to about 25, and wherein the oxyethyleneunits in such compounds constitute at least 15% by weight of suchcompounds. It is not necessary for all of the oxyethylene, oroxypropylene, units to be grouped together in any of theoxyethylene-containing materials described herein which are identifiedby formulas I, II and III. In other words, no particular order isrequired for such units in the compounds described in thisspecification. Accordingly, the compounds may be a block copolymer orrandom copolymer when m is greater than zero. In formula I above it ismost preferred that m is equal to zero and that the average value of nis in the range of 2 to 4. It also preferred that the viscosity of thecompound be less than 250 cps. Representative of the preferred compoundsof this formula are HOC₂ H₄ OC₂ H₄ OH, H(OC₂ H₄)₃ OH, H(OC₂ H₄)₄ OH,HOC₂ H₄ OC₃ H₆ OH, HOC₂ H₄ (OC₃ H₆)₂ OH, H(OC₂ H₄)₄ (OC₃ H₆)₆ OH, andH(OC₂ H₄)₂₂ OH.

Another class of useful oxyethylene containing compounds is that of theformula

    R[(OC.sub.2 H.sub.4).sub.n (OC.sub.3 H.sub.6).sub.m OH].sub.pII

where R is a polyvalent neutral linking organic radical. The term"neutral" means that the radical is essentially free of basic and acidicgroups (i.e. free of groups which have a base strength equal to orgreater than the amino group of aniline, and free of groups which havean acidity equal to or greater than phenol). Preferably R has less thanabout 25 carbon atoms and most preferably is a hydrocarbyl radical whichmay be aromatic, aliphatic or cyclic, although neutral substituents suchas NO₂, halogen, oxo, alkoxy, aliphatic hydroxyl, etc. are permissible.R may contain skeletal carbon-bonded oxygen or sulfur atoms bonded onlyto carbon. The valence of R is equal to p, which may range from 2 to 6.The sum of n and m is in the range of 1 to about 25. The oxyethyleneunits in such compounds constitute at least about 15% by weight of suchcompounds, and the number of carbon atoms in R divided by the product ofn and p is less than three. Preferably, m is equal to zero and theaverage value of n is 2 to 6. Representative examples of these compoundsinclude C₃ H₅ ](OC₂ H₄)OH]₃, C₃ H₅ [(OC₂ H₄)₂ OH]₃, C₄ H₈ [(OC₂ H₄)₄OH]₂, and C₆ H₄ [C₂ H₄ (OC₂ H₄)₃ (OC₃ H₆)₃ OH]₂. Mixtures of materialswith varying molecular weight, and of materials containing varyingoxyethylene and oxypropylene content are useful, generally typifycommercially available materials, and are sometimes preferred todecrease the melting point of pure materials.

Another class of useful oxyethylene-containing compounds is that of theformula

    R.sup.1 (OC.sub.2 H.sub.4).sub.n (OC.sub.3 H.sub.6).sub.m OHIII

where R¹ is a monovalent neutral organic radical. The term "Neutral" hasthe same meaning as defined above. Preferably R¹ has less than about 25carbon atoms and most preferably is a hydrocarbyl radical which may bearomatic, aliphatic or cyclic, although neutral substituents such asNO₂, halogen, oxo, alkoxyl. R may contain skeletal oxygen or sulfuratoms bonded only to carbon. The sum of n and m is in the range of 1 toabout 20. The oxyethylene units in such compounds constitute at leastabout 50% by weight of such compounds. Preferably, m is equal to zeroand the average value of n is 1 to 6. Representative examples of thesecompounds include CH₃ (OC₂ H₄)₂ OH, C₆ H₁₃ (OC₂ H₄)₅ (OC₃ H₆)₃, C₅ H₉ C₆H₄ (OC₂ H₄)₁₀ OH, and ClC₄ H₈ (OC₂ H₄)₈ OH.

EXAMPLE 1

A liquid solution is prepared containing a triarylsulfoniumhexafluorophosphate complex salt photoinitiator dissolved in diethyleneglycol at a concentration of 10% by weight.

The complex salt is prepared using as starting material atriarylsulfonium chloride prepared in accordance with the procedure ofexample 10 of U.S. Pat. No. 2,807,648 (Pitt), incorporated herein byreference. The product is dissolved in methyl alcohol, the solution isfiltered, and the filtrate is evaporated to leave a purified pale yellowcrystalline product. A solution of 8.95 parts of this product in 15parts of water is added to a solution of 5.52 parts of KPF₆ in 50 partsof water, with stirring, a copious precipitate forming. After stirringfor 10 minutes, there are added 40 parts by methylene chloride todissolve the precipitate. The methylene chloride phase is separated andwashed twice with 20 parts of water each time. The methylene chloridephase is then dried by adding thereto 0.5 part of anhydrous magnesiumsulfate which is thereafter removed by filtration. An equal weight ofacetone is added to the methylene chloride solution to form a 12% byweight solution of triarylsulfonium hexafluorophosphate complex salt.

While the complex salt can be recovered, for example, by drying underreduced pressure until solvent has evaporated, it is generally moreconvenient to maintain it in solution form. Diethylene glycol, HO(C₂ H₄O)₂ H, 16 parts, is added to 17 parts of the above solution of complexsalt. The resulting solution is placed in a rotary evaporator and heatedto 40°-50° C. The pressure is slowly reduced to about 10 torr until thebulk of the methylene chloride and acetone is removed, then furtherreduced to about 1 torr until evaporation essentially ceases. A crystalclear amber liquid (of complex salt dissolved in diethylene glycol) isobtained in which the complex salt is about 10% by weight.

EXAMPLES 2-3

Two photopolymerizable epoxy compositions are prepared, one of suchcompositions containing an organic material having at least one site ofnon-aromatic carbon-carbon unsaturation. The formulations of these twocompositions are as follows:

    ______________________________________                                        Example     Ingredients        Parts                                          ______________________________________                                        2           Solution of Example 1                                                                            20                                                         Epoxy resin ("ERL-4221")                                                                         80                                                         Surfactant         0.5                                            3           Solution of Example 1                                                                            20                                                         Epoxy resin ("ERL-4221")                                                                         77.5                                                       Surfactant         0.5                                                        trans-4-phenyl-3-butene-2-one                                                                    2.5                                            ______________________________________                                    

The nonionic surfactant which is present in the two examples is usedmerely to facilitate uniform spreading of the compositions on polyesterfilm which is the substrate to be coated in these examples. The presenceof a surfactant in these compositions is not always required, and manyconventional surfactants, fluorine-containing and fluorine-free, aresuitable for use.

A section of polyester film is coated in side-by-side strips with thetwo photopolymerizable compositions described above at a wet thicknessof about 10 microns using a quadragravure handproofer. The so-coatedfilm is then passed through an ultra-violet light processor (Model QC1202; Radiation Polymer Company) with two standaard medium pressure 200watts/inch mercury vapor lamps at a speed of 30 meters per minute.

The coating of Example 2, after exposure, exhibits a pronouncedorgano-sulfur odor; whereas, the cured coating of Example 3 exhibits nodetectable odor. It is also observed that the composition of Example 3exhibited a slightly more yellow color than the composition of Example 2prior to curing, but after curing the composition of Example 3 exhibitedless yellow color than that of Example 2.

EXAMPLES 4-6

Example 3 is repeated using other unsaturated organic materials of thetype, and in the amounts, listed in the following table; in each examplethe total weight of epoxy plus unsaturated material is 80 parts.

    ______________________________________                                        Example    Unsaturated Material                                                                            Parts                                            ______________________________________                                        4          2-butene-1,4-diol  5                                               5          "                 10                                               6          diallyl phthalate 20                                               ______________________________________                                    

Each composition, after photo curing, exhibits little or no detectableorgano-sulfur odor.

EXAMPLES 7-22

Several photopolymerizable compositions are prepared illustrating theuse of various types of unsaturated organic materials for the purposesof reducing or eliminating organo-sulfur odor upon photo curing of suchcompositions. In each example the composition consists of theingredients used in Example 3, except that the particular unsaturatedorganic material used, and the amount thereof, is that listed in thefollowing table; in each example the total weight of epoxy plusunsaturated material is 80 parts.

    ______________________________________                                        Example    Unsaturated Material                                                                             Parts                                           ______________________________________                                         7         1,5-diphenyl-3-pentadienone                                                                      10                                               8         1,5-diphenyl-3-pentadienone                                                                      5                                                9         trans-4-phenyl-3-butene-2-one                                                                    5                                               10         trans-4-phenyl-3-butene-2-one                                                                    2                                               11         cinnamyl maleate   10                                              12         cinnamic acid      5                                               13         methyl cinnamate   5                                               14         ethyl cinnamate    5                                               15         ethyl cinnamate    2.5                                             16         ethyl cinnamate    2                                               17         ethyl cinnamate    1.5                                             18         butyl cinnamate    5                                               19         butyl cinnamate    2                                               20         coumarin           5                                               21         6-methyl-coumarin  5                                               22         6-methyl-coumarin  2                                               ______________________________________                                    

What is claimed is:
 1. A liquid composition consisting essentiallyof:(a) aromatic sulfonium complex salt, said salt beingphotodecomposable and being capable of initiating polymerization ofcationically polymerizable monomers upon exposure to actinic radiation;(b) at least about 15% by weight of liquid neutraloxyethylene-containing material selected from:(i) compounds having theformula

    R[(OC.sub.2 H.sub.4).sub.n (OC.sub.3 H.sub.6).sub.m OH].sub.p

where R is a polyvalent neutral organic radical having a valence of p,n+m is in the range of 1 to about 25, p is in the range of 2 to 6,wherein the oxyethylene units in such compounds constitute at leastabout 15% by weight of such compounds; and wherein the number of carbonatoms in R divided by the product of n and p is less than three; and(ii) compounds having the formula:

    R.sup.1 (OC.sub.2 H.sub.4).sub.n (OC.sub.3 H.sub.6).sub.m OH

where R¹ is monovalent neutral organic radical, where n+m is in therange of 1 to 25, wherein the oxyethylene units in such compoundsconstitute at least about 50% by weight of such compounds; and (iii)compounds of the formula:

    H(OC.sub.2 H.sub.4).sub.n (OC.sub.3 H.sub.6).sub.m OH

where n+m is in the range of 2 to about 25, wherein the oxyethyleneunits in such compounds constitute at least about 15% by weight of suchcompounds; and (c) an organic material containing at least one site ofnon-aromatic carbon-carbon unsaturation; wherein said unsaturation insaid organic material is ethylenic and wherein each ethylenicallyunsaturated carbon atom has no more than one hydrogen atom bondedthereto; and wherein said organic material is present in an amount ofabout 0.5 to 20% by weight of said composition.
 2. A liquid compositionin accordance with claim 1, wherein at least one of said ethylenicallyunsaturated carbon atoms has bonded thereto a C=O group.
 3. A liquidcomposition in accordance with claim 1, wherein said complex salt is ofthe formula

    [(R).sub.a (R.sup.1).sub.b (R.sup.2).sub.c S].sub.d.sup.+ [MQ.sub.e ].sup.-(e-f)

where R is a monovalent aromatic organic radical, R¹ is a monovalentorganic aliphatic radical selected from alkyl, cycloalkyl andsubstituted alkyl, R² is a polyvalent organic radical forming aheterocyclic or fused ring structure selected from aliphatic radicalsand aromatic radicals, M is a metal or metalloid, Q is a halogenradical, a is a whole number equal to 0 to 3 inclusive, b is a wholenumber equal to 0 to 2 inclusive, c is a whole number equal to 0 or 1,where the sum of a+b+c is a value equal to 3, d=e-f, f is equal to thevalence of M and is an integer equal to from 2 to 7 inclusive, e isgreater than f and is an integer having a value up to
 8. 4. A liquidcomposition in accordance with claim 3, wherein a is equal to 3, M isselected from P or Sb, and Q is F.
 5. A liquid composition in accordancewith claim 1, wherein said oxyethylene-containing material is selectedfrom H(OC₂ H₄)₂ OH, H(OC₂ H₄)₃ OH, H(OC₂ H₄)₄ OH, HOC₂ H₄ OC₃ H₆ OH,HOC₂ H₄ (OC₃ H₆)₂ OH, H(OC₂ H₄)₄ (OC₃ H₆)₆ OH and H(OC₂ H₄)₂₂ OH.
 6. Aliquid composition in accordance with claim 1, wherein saidoxyethylene-containing material is selected from C₃ H₅ [(OC₂ H₄)OH]₃, C₃H₅ [(OC₂ H₄)₂ OH]₃, C₄ H₈ [(OC₂ H₄)₄ OH]₂, and C₆ H₄ [C₂ H₄ (OC₂ H₄)₃(OC₃ H₆)₃ OH]₂.